Combined IV and intra-arterial thrombolysis for acute ischemic stroke

Low-dose intravenous tissue plasminogen activator for acute ischaemic stroke: an alternative or a new standard?

BACKGROUND

With the recent publication of a large clinical trial on the use of a lower dose of intravenous (IV) tissue plasminogen activator (tPA) for acute ischaemic stroke (AIS), the concept of using a different dose has been debated. We intend to review the literature on using a lower dose of IV tPA and gain a better understanding of the impact of different IV doses on the treatment of patients with AIS.

METHODS

A comprehensive literature search of the related topics in PubMed, EMBASE, Web of Science and MEDLINE was carried out. Key words used include low dose IV tPA, thrombolysis, Alteplace and tPA for AIS. Findings were tabulated according to the size of the cohort studied, outcome, adverse event and level of evidence. The results of all studies using lower doses were analysed for efficacy and adverse events.

RESULTS

From 1992 to 2016, there were 23 trials that included 10 950 patients published on the use of lower doses of IV tPA for AIS. Doses ranged from 0.5, 0.6, 0.75 to 0.85 mg/kg. Most were observational, retrospective and registry studies. One was a prospective open-label randomised controlled trial. 13 trials combined lower doses of IV tPA with a glycoprotein IIb/IIIa inhibitor or thrombectomy. Patients treated with lower doses of IV tPA showed a trend of lower rate of symptomatic intracranial haemorrhage and mortality at 3 months but slightly more disability.

CONCLUSIONS

Lower doses of IV tPA showed less haemorrhagic events but were not more effective compared with the standard dose. The optimal low dose of IV tPA remains unclear. Patients with AIS with a high risk of developing sypmtomatic intracranial haemorrhage might benefit from lower dose IV tPA, such as 0.6 mg/kg.

Endovascular revascularization results in IMS III: intracranial ICA and M1 occlusions

BACKGROUND

Interventional Management of Stroke III did not show that combining IV recombinant tissue plasminogen activator (rt-PA) with endovascular therapies (EVTs) is better than IV rt-PA alone.

OBJECTIVE

To report efficacy and safety results for EVT of intracranial internal carotid artery (ICA) and middle cerebral artery trunk (M1) occlusion.

METHODS

Five revascularization methods for persistent occlusions after IV rt-PA treatment were evaluated for prespecified primary and secondary endpoints, after accounting for differences in key baselines variables using propensity scores. Revascularization was scored using the arterial occlusive lesion (AOL) and the modified Thrombolysis in Cerebral Ischemia (mTICI) scores.

RESULTS

EVT of 200 subjects with intracranial ICA or M1 occlusion resulted in 81.5% AOL 2-3 recanalization, in addition to 76% mTICI 2-3 and 42.5% mTICI 2b-3 reperfusion. Adverse events included symptomatic intracranial hemorrhage (SICH) (8.0%), vessel perforations (1.5%), and new emboli (14.9%). EVT techniques used were standard microcatheter n=51; EKOS n=14; Merci n=77; Penumbra n=39; Solitaire n=4; multiple n=15. Good clinical outcome was associated with both TICI 2-3 and TICI 2b-3 reperfusion. Neither modified Rankin scale (mRS) 0-2 (28.5%), nor 90-day mortality (28.5%), nor asymptomatic ICH (36.0%) differed among revascularization methods after propensity score adjustment for subjects with intracranial ICA or M1 occlusion.

CONCLUSIONS

Good clinical outcome was associated with good reperfusion for ICA and M1 occlusion. No significant differences in efficacy or safety among revascularization methods were demonstrated after adjustment. Lack of high-quality reperfusion, adverse events, and prolonged time to treatment contributed to lower-than-expected mRS 0-2 outcomes and study futility compared with IV rt-PA.

TRIAL REGISTRATION NUMBER

NCT00359424.

Alteplase for acute ischemic stroke

Alteplase, an intravenously administered form of recombinant tissue plasminogen activator (rt-PA), remains the only US FDA-approved thrombolytic treatment for acute ischemic stroke within 3 h of symptom onset. Patients treated with intravenous rt-PA are at least 30% more likely to have minimal or no disability at 3 months compared with placebo. Despite an increased risk of symptomatic intracranial hemorrhage, rt-PA does not increase mortality. The benefit achieved with rt-PA is cost effective and sustained 1 year after treatment. Despite its clear benefit, rt-PA remains underutilized. Although the future of acute ischemic stroke treatment will most likely involve a multi-faceted treatment approach, the primary objective remains to establish recanalization of the involved vessel. For patients with acute ischemic stroke within the first 3 h of symptom onset, rt-PA remains the first step in accomplishing this goal.

Drug treatment of acute ischemic stroke

Acute ischemic stroke (AIS) is the fourth leading cause of death and the leading cause of adult disability in the USA. AIS most commonly occurs when a blood vessel is obstructed leading to irreversible brain injury and subsequent focal neurologic deficits. Drug treatment of AIS involves intravenous thrombolysis with alteplase (recombinant tissue plasminogen activator [rtPA]). Intravenous alteplase promotes thrombolysis by hydrolyzing plasminogen to form the proteolytic enzyme plasmin. Plasmin targets the blood clot with limited systemic thrombolytic effects. Alteplase must be administered within a short time window to appropriate patients to optimize its therapeutic efficacy. Recent trials have shown this time window may be extended from 3 to 4.5 hours in select patients. Other acute supportive interventions for AIS include maintaining normoglycemia, euthermia and treating severe hypertension. Urgent anticoagulation for AIS has generally not shown benefits that exceed the hemorrhage risks in the acute setting. Urgent antiplatelet use for AIS has limited benefits and should only promptly be initiated if alteplase was not administered, or after 24 hours if alteplase was administered. The majority of AIS patients do not receive thrombolytic therapy due to late arrival to emergency departments and currently there is a paucity of acute interventions for them. Ongoing clinical trials may lead to further medical breakthroughs to limit the damage inflicted by this devastating disease.

Combined full-dose IV and endovascular thrombolysis in acute ischaemic stroke

BACKGROUND

There is an increasing trend to treating proximal vessel occlusions with intravenous-inter-arterial (IV-IA) thrombolysis. The best dose of IV tissue plasminogen activator (tPA) remains undetermined. We compared the combination of full-dose IV recombinant tissue plasminogen activator (rtPA) and IA thrombolytic therapy to IA therapy.

METHODS

Between 2002 and 2009, we reviewed our computed tomographic angiography database for patients who received full-dose intravenous rtPA and endovascular therapy or endovascular therapy alone for acute ischaemic stroke treatment. Details of demographics, risk factors, endovascular procedure, and symptomatic intracranial haemorrhage were noted. Modified Rankin Scale ≤2 at three-months was used as good outcome. Recanalization was defined as Thrombolysis in Myocardial Ischaemia 2-3 flow on angiography.

RESULTS

Among 157 patients, 104 patients received IV-IA treatment and 53 patients underwent direct IA therapy. There was a higher recanalization rate with IV-IA therapy compared with IA alone (71% vs. 60%, P < 0·21) which was driven by early recanalization after IV rtPA. Mortality and independent outcome were comparable between the two groups. Symptomatic intracranial haemorrhage occurred in 8% of patients (12% in the IA group, 7% in the IV-IA group) but was more frequent as the intensity of intervention increased from device alone to thrombolytic drug alone to device plus thrombolytic drug(s). Recanalization was a strong predictor of reduced mortality risk ratio (RR) 0·48 confidence interval95 0·27-0·84) and favourable outcome (RR 2·14 confidence interval95 1·3-3·5).

CONCLUSIONS

Combined IV-IA therapy with full-dose intravenous rtPA was safe and results in good recanalization rates without excess symptomatic intracranial haemorrhage. Testing of full-dose IV tPA followed by endovascular treatment in the IMS3 trial is justified.

Developing practice recommendations for endovascular revascularization for acute ischemic stroke

Guidelines have been established for the management of acute ischemic stroke; however, specific recommendations for endovascular revascularization therapy are lacking. Burgeoning investigation of endovascular revascularization therapies for acute ischemic stroke, rapid device development, and a diverse training background of the providers performing the procedures underscore the need for practice recommendations. This review provides a concise summary of the Society of Vascular and Interventional Neurology endovascular acute ischemic stroke roundtable meeting. This document was developed to review current clinical efficacy of pharmacologic and mechanical revascularization therapy, selection criteria, periprocedure management, and endovascular time metrics and to highlight current practice patterns. It therefore provides an outline for the future development of multisociety guidelines and recommendations to improve patient selection, procedural management, and organizational strategies for revascularization therapies in acute ischemic stroke.

Elderly Patients Are at Higher Risk for Poor Outcomes After Intra-Arterial Therapy

Background and Purpose—

Conflicting data exist regarding outcomes after intra-arterial therapy (IAT) in elderly stroke patients. We compare safety and clinical outcomes of multimodal IAT in elderly versus nonelderly patients and investigate differences in baseline health and disability as possible explanatory factors.

Methods—

Data from a prospectively collected institutional IAT database were analyzed comparing elderly (80 years or older) versus nonelderly patients. Baseline demographics, angiographic reperfusion (Thrombolysis in Cerebral Infarction scale score 2–3), rate of parenchymal hematoma type 2, and 90-day modified Rankin Scale scores were compared in univariate and multivariate analyses.

Results—

There were 49 elderly and 130 nonelderly patients treated between 2005 and 2010. Between the 2 cohorts, there was no significant difference in Thrombolysis in Cerebral Infarction 2 to 3 reperfusion (71% vs 75%; P =0.57), time to reperfusion ( P =0.77), or rate of parenchymal hematoma type 2 (4% vs 7%; P =0.73) after IAT. However, elderly patients had significantly lower rates of good outcome (modified Rankin Scale score 0–2: 2% vs 33%; P <0.0001) and higher mortality (59% vs 24%; P <0.0001) at 90 days. Atrial fibrillation, coronary artery disease, hypertension, hyperlipidema, and baseline disability were significantly more common in elderly patients. Adjusting for baseline disability, stroke severity, and reperfusion, elderly patients were 29-times more likely to be dependent or dead at 90 days (odds ratio, 28.7; 95% confidence interval, 3.2–255.7; P =0.003).

Conclusions—

Despite comparable rates of reperfusion and significant hemorrhage, elderly patients had worse clinical outcomes after IAT, which may relate, in part, to worse baseline health and disability. The use of IAT in the elderly should be performed after a careful analysis of the potential risks and benefits.

Bridging therapy in acute ischemic stroke: a systematic review and meta-analysis

BACKGROUND AND PURPOSE

Pending the results of randomized controlled trials, the benefit and safety of bridging therapy (combined intravenous and intra-arterial thrombolysis) remain to be determined. The aim of this analysis was to give reliable estimates of efficacy and safety outcomes of bridging therapy.

METHODS

We conducted a systematic review of all studies using bridging therapy published between January 1966 and March 2011.

RESULTS

The literature search identified 15 studies. The pooled estimate for recanalization rate was 69.6% (95% CI, 63.9%-75.0%). Meta-analysis on clinical outcomes showed a pooled estimate of 48.9% (95% CI, 42.9%-54.9%) for favorable outcome, 17.9% (95% CI, 12.7%-23.7%) for mortality, and 8.6% (95% CI, 6.8%-10.6%) for symptomatic intracranial hemorrhage. In meta-regression analysis, the shorter mean time to intravenous treatment, the greater the recanalization rate (per 10-minute decrease: OR, 1.24; 95% CI, 1.02-1.51) and the lower mortality rate (per 10-minute decrease: OR, 0.75; 95% CI, 0.60-0.94). By using the control groups of intravenous alteplase-treated patients in 8 studies, bridging therapy was associated with a favorable outcome (OR, 2.26; 95% CI, 1.16-4.40), but no differences in mortality or symptomatic intracranial hemorrhage outcomes were found.

CONCLUSIONS

Bridging therapy is associated with acceptable safety and efficacy in stroke patients. Time to intravenous treatment is critical to improve recanalization rates and favorable outcomes.

Endovascular treatment of acute ischemic stroke: current indications

Endovascular stroke therapy is an effective means of achieving reperfusion in stroke patients with proximal cerebral artery occlusions. However, current guideline recommendations express uncertainty regarding the clinical efficacy of catheter-based treatments, given the lack of supportive trial data. A critical problem is that it remains unclear which patients will benefit from endovascular therapy. As such, patient selection is likely highly variable in clinical practice. This article will review the existing data to discuss the clinical and imaging factors that are relevant to patient outcomes, and which may be used to guide endovascular treatment decisions. Anterior circulation strokes represent the primary focus of this review.

Safety of full-dose intravenous recombinant tissue plasminogen activator followed by multimodal endovascular therapy for acute ischemic stroke

BACKGROUND AND PURPOSE

The optimal management of stroke patients who fail treatment with intravenous recombinant tissue plasminogen activator (rt-PA) remains unknown. A study was undertaken to establish whether treatment with a standard intravenous t-PA dose (0.9 mg/kg) followed by multimodal endovascular therapy would have a similar safety profile to reduced dose (0.6 mg/kg) bridging therapy.

METHODS

A retrospective analysis was performed of a prospectively collected database. All patients treated with full-dose t-PA and endovascular therapy were included. The primary safety endpoints included ECASS-III symptomatic intracranial hemorrhage (sICH) and ECASS parenchymal hematomas (PH). Secondary safety endpoints included severe systemic bleeding and 90-day mortality. Clinical efficacy endpoints included rates of recanalization (TICI 2-3), ambulation at hospital discharge and 90-day independent outcomes (mRS 0-2).

RESULTS

106 consecutive patients (mean age 69 ± 17 years; mean baseline NIH Stroke Scale 17.8 ± 4.8; 55% women; occlusion sites: MCA-M1 60.4%; MCA-M2 6.6%; ICA-T 19.8%; tandem cervical ICA+MCA-M1 7.5%; basilar artery 5.7%) were identified over a 10-year period. The sICH rate was 8.5% and the PH-1, PH-2 and subarachnoid hemorrhage rates were 2.8%, 8.5% and 2.8%, respectively. There were two (1.9%) severe groin hematomas. The recanalization rate was 66%. At hospital discharge, 41.4% of the patients were ambulatory. The rate of independent functional outcomes at 90 days was 24%; however, this sample is biased since nearly all deaths were captured but detailed 90-day functional outcomes were missing in 27 patients. The 90-day death rate was 32.4%.

CONCLUSION

Combined treatment with full-dose intravenous rt-PA followed by multimodal endovascular therapy seems to be associated with similar rates of sICH to that of bridging therapy with reduced rt-PA dosage.

Correlation between Serum D-Dimer Level and Volume in Acute Ischemic Stroke

OBJECTIVE

D-dimer is a breakdown product of fibrin mesh after factor XIII stabilization. Previously, many authors have demonstrated a relationship between D-dimer level and stroke progression or type. This study aimed to investigate the relationship between D-dimer level and stroke volume.

METHODS

Between January 2008 and December 2009, we analyzed the D-dimer levels of 59 acute ischemic stroke patients in our neurosurgical department both upon admission and after seven days of initial treatment. Each patient's National Institute of Health Stroke Scale score, modified Rankin Scales score, Glasgow outcome score, and infarction volume were also evaluated.

RESULTS

Mean D-dimer level at admission was 626.6 µg/L (range, 77-4,752 µg/L) and the mean level measured after seven days of treatment was 238.3 µg/L (range, 50-924 µg/L). Mean D-dimer level at admission was 215.3 µg/L in patients with focal infarctions, 385.7 µg/L in patients with multiple embolic infarctions, 566.2 µg/L in those with 1-19 cc infarctions, 668.8 µg/L in 20-49 cc infarctions, 702.5 µg/L in 50-199 cc infarctions, and 844.0 µg/L in >200 cc infarctions (p=0.044). On the 7th day of treatment, the D-dimer levels had fallen to 201.0 µg/L, 293.2 µg/L, 272.0 µg/L, 232.8 µg/L, 336.6 µg/L, and 180.0 µg/L, respectively (p=0.530).

CONCLUSION

Our study shows that D-dimer level has the positive correlation with infarction volume and can be use to predict infarction-volume.

Impact of a combined intravenous/intra-arterial approach in octogenarians

BACKGROUND

Intravenous (IV) alteplase is not currently recommended in octogenarian patients, and the benefit/risk ratio of endovascular (intra-arterial, IA) therapy remains to be determined. The aim of this study was to determine the impact of a combined IV-IA approach in octogenarians.

METHODS

From a single-centre interventional study, we report age-specific outcomes of patients treated by a combined IV-IA thrombolytic approach. Patients ≥80 years with documented arterial occlusion treated by conventional IV thrombolysis constituted the control group.

RESULTS

Among 84 patients treated by the IV-IA approach, those ≥80 years (n = 25) had a similar rate of early neurological improvement to that of patients <80 years, whereas the 90-day favourable outcome rate was lower in octogenarians (adjusted odds ratio, OR, 0.21; 95% confidence interval, CI, 0.06-0.75). No difference in symptomatic intracranial haemorrhage was observed whereas a higher rate of 90-day mortality (adjusted OR, 3.27; 95% CI, 0.76-14.14) and asymptomatic intracranial haemorrhage (adjusted OR, 6.39; 95% CI, 1.54-26.63) were found in patients ≥80 years old. Among octogenarians, and compared to IV-thrombolysis-treated patients (n = 24), patients treated by the IV-IA approach had a higher rate of recanalization (76 vs. 33%, p = 0.003) associated with increased early neurological improvement (32 vs. 8%, p = 0.07). Although there was a higher rate of asymptomatic intracranial haemorrhage (44 vs. 8%, p = 0.005) observed in the IV-IA group, no difference existed in symptomatic intracranial haemorrhage rates and 90-day favourable outcome.

CONCLUSION

The IV-IA approach in octogenarians was associated with lower efficacy at 3 months and higher mortality and asymptomatic haemorrhagic complications than in patients <80 years old. Definite recommendations cannot be given, but an endovascular approach may cause more harm than positive effects in patients over 80 years and should not be considered outside an approved protocol.

Endovascular stroke treatment today

The purpose of this study was to review current treatment options in acute ischemic stroke, focusing on the latest advances in the field of mechanical recanalization. These devices recently made available for endovascular intracranial thrombectomy show great potential in acute stroke treatments. Compelling evidence of their recanalization efficacy comes from current mechanical embolectomy trials. In addition to allowing an extension of the therapeutic time window, mechanical recanalization devices can be used without adjuvant thrombolytic therapy, thus diminishing the intracranial bleeding risk. Therefore, these devices are particularly suitable in patients in whom thrombolytic therapy is contraindicated. IV and IA thrombolysis and bridging therapy are viable options in acute stroke treatment. Mechanical recanalization devices can potentially have a clinically relevant impact in the interventional treatment of stroke, but at the present time, a randomized study would be beneficial.

Comparison of acute nonthrombolytic and thrombolytic treatments in ischemic stroke patients 80 years or older

OBJECTIVES

The aim of this study was to compare the clinical outcomes of acute ischemic stroke patients 80 years or older treated with intravenous recombinant tissue plasminogen activator (i.v. rt-PA), or endovascular intervention with or without i.v. rt-PA, or nonthrombolytic medical treatment.

METHODS

This study was a retrospective, nonrandomized, observational study of patients, admitted within 9 hours of symptom onset, at 3 academic, university-affiliated hospitals. The main outcome measures were neurologic improvement, defined by improvement in National Institutes of Health Stroke Scale score at 7 days or discharge of 4 or more, or achieving a score of 0; symptomatic and asymptomatic intracerebral hemorrhage; favorable outcome (discharge modified Rankin score 0-2); and in-hospital mortality.

RESULTS

A total of 44 patients received i.v. rt-PA, 46 received endovascular intervention with or without i.v. rt-PA, and 66 received nonthrombolytic medical treatment. I.v. rt-PA-treated patients had a significantly clinically higher chance of favorable outcome (odds ratio [OR], 5.6; 95% confidence interval [CI], 1.8-17.5), when compared with nonthrombolytic medical treatment. A significantly higher rate of neurologic improvement was observed among the i.v. rt-PA (7.2; 95% CI, 2.7-19.5) and endovascularly treated patients (5.8; 95% CI, 2-16.8) when compared with nonthrombolytic medical treatment.

CONCLUSIONS

A prominently higher rate of neurologic improvement and favorable clinical outcome was observed among acute ischemic stroke patients 80 years or older treated with i.v. rt-PA or endovascular intervention when compared with nonthrombolytic medical treatment, supporting the use of acute thrombolytic therapies in this patient population when contraindications are not present.

Is mechanical embolectomy performed in nonanesthetized patients effective?

BACKGROUND AND PURPOSE

In centers performing endovascular treatment for patients with AIS, there is variability in placing patients under general anesthesia. Nonanesthetized patients might move during the procedure leading to complications and prolonging the time to revascularization due to lack of cooperation. However, general anesthesia can lead to a delay of the procedure, an inability to assess the patient during the procedure, and fluctuations of blood pressure. Our center does not routinely either use general anesthesia or sedate patients. We report our experience with nonanesthetized patients undergoing emergent mechanical embolectomy.

MATERIALS AND METHODS

We performed a retrospective analysis of 66 consecutive patients enrolled in the MERCI Registry at our center from June 2007 to June 2009. A univariate statistical analysis was performed by using the Fisher exact test for categoric variables and the Student t test for continuous variables in comparing use of general anesthesia with nonanesthetized patient demographics, procedural times, procedural complications, good outcome, and mortality.

RESULTS

Nine patients (13.6%) were placed under general anesthesia, and 57 (86.4%) were awake. Higher baseline NIHSS scores and older age were statistically associated with general anesthesia. No significant difference occurred between groups in the time to groin puncture or procedural times. Revascularization rates were 77% for general anesthesia patients and 70% for nonanesthetized patients (P = .331). The nonanesthetized group had better outcomes, but we did not control these outcomes for other factors. Complications were much more frequent in the general anesthesia patients (22%) than in the nonanesthetized patients (3.5%) (P = .0288).

CONCLUSIONS

Performing mechanical embolectomy in nonanesthetized patients at our institution does not prolong procedure time, decrease revascularization rates, increase complication rates, or decrease good outcome. Mechanical embolectomy in nonanesthetized patients is effective and should be considered an option in the treatment of the patient with AIS.

Intravenous rt-PA versus endovascular therapy for acute ischemic stroke

The influence of baseline stroke severity on outcome makes comparisons between nonrandomized studies of intravenous and intra-arterial (IA) therapy problematic. Using pooled data from the placebo arms of randomized trials in acute ischemic stroke, we derived predictive functions for outcome. We then compared the outcomes from published trials to these functions. Net benefit was calculated by comparison of the individual study with the predicted outcome based on the therapeutic time window. Similar net benefit for IA therapy and intravenous therapy was found at 3 hours and 6 hours; a slight advantage for IA therapy was mitigated by an increase in mortality at 6 hours and by publication bias. No net benefit for IA therapy was shown in the time window greater than 6 hours. Conclusive evidence for the superiority of either therapy awaits prospective randomized trials.

Conscious Sedation Versus General Anesthesia During Endovascular Therapy for Acute Anterior Circulation Stroke

Background and Purpose— Patients undergoing intra-arterial therapy (IAT) for acute ischemic stroke receive either general anesthesia (GA) or conscious sedation. GA may delay time to treatment, whereas conscious sedation may result in patient movement and compromise the safety of the procedure. We sought to determine whether there were differences in safety and outcomes in GA patients before initiation of IAT.

Methods— A cohort of 980 patients at 12 stroke centers underwent IAT for acute stroke between 2005 and 2009. Only patients with anterior circulation strokes due to large-vessel occlusion were included in the study. A binary logistic-regression model was used to determine independent predictors of good outcome and death.

Results— The mean age was 66±15 years and median National Institutes of Health Stroke Scale score was 17 (interquartile range, 13–20). The overall recanalization rate was 68% and the symptomatic hemorrhage rate was 9.2%. GA was used in 44% of patients with no differences in intracranial hemorrhage rates when compared with the conscious sedation group. The use of GA was associated with poorer neurologic outcome at 90 days (odds ratio=2.33; 95% CI, 1.63–3.44; P <0.0001) and higher mortality (odds ratio=1.68; 95% CI, 1.23–2.30; P <0.0001) compared with conscious sedation.

Conclusions— Patients placed under GA during IAT for anterior circulation stroke appear to have a higher chance of poor neurologic outcome and mortality. There do not appear to be differences in hemorrhagic complications between the 2 groups. Future clinical trials with IAT can help elucidate the etiology of the differences in outcomes.

Equipoise among recanalization strategies

Modern acute ischemic stroke therapy is based on the premise that recanalization and subsequent reperfusion are essential for the preservation of brain tissue and favorable clinical outcomes. We outline key issues that we think underlie equipoise regarding the comparative clinical efficacy of IV recombinant tissue-type plasminogen activator (rt-PA) and intra-arterial (IA) reperfusion therapies for acute ischemic stroke. On the one hand, IV rt-PA therapy has the benefit of speed with presumed lower rates of recanalization of large artery occlusions as compared to IA methods. More recent reports of major arterial occlusions treated with IV rt-PA, as measured by transcranial Doppler and magnetic resonance angiography, demonstrate higher rates of recanalization. Conversely, IA therapies report higher recanalization rates, but are hampered by procedural delays and risks, even failing to be applied at all in occasional patients where time to reperfusion remains a critical factor. Higher rates of recanalization in IA trials using clot-removal devices have not translated into improved patient functional outcome as compared to trials of IV therapy. Combined IV-IA therapy promises to offer advantages of both, but perhaps only when applied in the timeliest of fashions, compared to IV therapy alone. Where equipoise exists, randomizing subjects to either IV rt-PA therapy or IV therapy followed by IA intervention, while incorporating new interventions into the study design, is a rational and appropriate research approach.

Intra-arterial recanalization techniques for patients 80 years or older with acute ischemic stroke: pooled analysis from 4 prospective studies

BACKGROUND AND PURPOSE

Previous studies have demonstrated limited benefit with endovascular procedures such as stent placement in octogenarians. We evaluated the safety and effectiveness of intra-arterial recanalization techniques to treat ischemic stroke in patients 80 years or older presenting within 6 hours of symptom onset.

MATERIALS AND METHODS

We pooled the data from 4 prospective studies by evaluating intra-arterial recanalization techniques for treatment of ischemic stroke. Clinical and radiologic evaluations were performed before treatment and at 24 hours, 7 to 10 days, and 1 to 3 months after treatment. We performed multivariate analyses to evaluate the effect of ages 80 years and older on angiographic recanalization, favorable outcome (modified Rankin scale of 0-2), and mortality rate at 1 to 3 months.

RESULTS

A total of 101 patients were treated in the 4 protocols. Of these, 24 were 80 years or older. There was no significant difference between the 2 age groups in sex, initial stroke severity, time to treatment, site of vascular occlusion, and rate of symptomatic and asymptomatic intracranial hemorrhage (ICH). In logistic regression analysis, age 80 years or older was associated with a lower likelihood of a favorable outcome (odds ratio [OR], 0.40; 95% confidence interval [CI], 0.13-1.2; P = .11) and recanalization (OR, 0.36; 95% CI, 0.12-1.1; P = .07) and with higher mortality rate (OR, 3.17; 95% CI, 1.05-9.55; P = .04) after adjusting for study protocol. After adjusting for recanalization in addition to study protocol, the older age group still had a lower likelihood of favorable outcomes (OR, 0.34; 95% CI, 0.1-1.1; P = .07) and higher mortality rates (OR, 3.62; 95% CI, 1.15-11.36; P = .027).

CONCLUSIONS

Our study demonstrates that patients 80 years and older are at higher risk for poor outcome at 1 to 3 months following intra-arterial recanalization techniques. This relationship is independent of recanalization rate and symptomatic ICH supporting the role of other mechanisms.

Risk of symptomatic intracerebral hemorrhage in patients treated with intra-arterial thrombolysis

BACKGROUND

In intra-arterial (IA) thrombolysis trials, higher rates of symptomatic intracerebral haemorrhage (sICH) were found than in trials with intravenous (IV) recombinant tissue plasminogen activator (tPA); this observation could have been due to the inclusion of more severely affected patients in IA thrombolysis trials. In the present study, we investigated the rate of sICH in IA and combined IV + IA thrombolysis versus IV thrombolysis after adjusting for differences in clinical and MRI parameters.

METHODS

In this multicenter study, we systematically analyzed data from 645 patients with anterior-circulation strokes treated with either IV or IA thrombolysis within 6 h following symptom onset. Thrombolytic regimens included (1) IV tPA treatment (n = 536) and (2) IA treatment with either tPA or urokinase (n = 74) or (3) combined IV + IA treatment with either tPA or urokinase (n = 35).

RESULTS

44 (6.8%) patients developed sICH. sICH patients had significantly higher scores on the National Institutes of Health Stroke Scale (NIHSS) at admission and pretreatment DWI lesions. The sICH risk was 5.2% (n = 28) in IV thrombolysis, which is significantly lower than in IA (12.5%, n = 9) or IV + IA thrombolysis (20%, n = 7). In a binary logistic regression analysis including age, NIHSS score, time to thrombolysis, initial diffusion weighted imaging lesion size, mode of thrombolytic treatment and thrombolytic agent, the mode of thrombolytic treatment remained an independent predictor for sICH. The odds ratio for IA or IV + IA versus IV treatment was 3.466 (1.19-10.01, 95% CI, p < 0.05).

CONCLUSION

In this series, IA and IV + IA thrombolysis is associated with an increased sICH risk as compared to IV thrombolysis, and this risk is independent of differences in baseline parameters such as age, initial NIHSS score or pretreatment lesion size.

Methodology of the Interventional Management of Stroke III Trial

RATIONALE

The Interventional Management of Stroke (IMS) I and II pilot trials demonstrated that the combined intravenous (i.v.) and intraarterial (i.a.) approach to recanalization may be more effective than standard i.v. rt-PA (Activase) alone for moderate-to-large National Institutes of Health Stroke Scale (NIHSS>or=10) strokes, and with a similar safety profile.

AIMS

The primary objective of this NIH-funded, Phase III, randomized, multicenter, open-label clinical trial is to determine whether a combined i.v./i.a. approach to recanalization is superior to standard i.v. rt-PA alone when initiated within 3 h of acute ischemic stroke onset. The IMS III trial will develop and maintain a network of interventional centers to test the safety, feasibility, and potential efficacy of new FDA-approved catheter devices as part of a combined i.v./i.a. approach to recanalization as the IMS III study progresses. A secondary objective of the IMS III trial is to determine the cost-effectiveness of the combined i.v./i.a. approach as compared with standard i.v. rt-PA. Trial enrollment began in July of 2006.

DESIGN

A projected 900 subjects with moderate-to-large (NIHSS>or=10) ischemic strokes between ages 18 and 80 will be enrolled over the next 5 years at 40-plus centers in the United States and Canada. Patients must have i.v. treatment initiated within 3 h of stroke onset in both arms. Subjects will be randomized in a 2 : 1 ratio with more subjects enrolled in the combined i.v./i.a. group. The i.v. rt-PA alone group will receive the standard full dose [0.9 mg/kg, 90 mg maximum (10% as bolus)] of rt-PA intravenously over an hour. The combined i.v./i.a. group will receive a lower dose of i.v. rt-PA ( approximately 0.6 mg/kg, 60 mg maximum) over 40 min, followed by immediate angiography. If a treatable thrombus is not demonstrated, no i.a. therapy will be administered. If an appropriate thrombus is identified, treatment will continue with either the Concentric Merci thrombus-removal device, infusion of rt-PA and delivery of low-intensity ultrasound at the site of the occlusion via the EKOS Micro-Infusion Catheter, or infusion of rt-PA via a standard microcatheter. If i.a. rt-Pa therapy is the chosen strategy, a maximum of 22 mg of i.a. rt-PA may be given. The choice of i.a. strategy will be made by the treating neurointerventionalist. The i.a. treatment must begin within 5 h and be completed within 7 h of stroke onset.

STUDY OUTCOMES

The primary outcome measure is a favorable clinical outcome, defined as a modified Rankin Scale Score of 0-2 at 3 months. The primary safety measure is mortality at 3 months and symptomatic ICH within the 24 h of randomization.

Combined intravenous and intraarterial revascularization therapy using MRI perfusion/diffusion mismatch selection for acute ischemic stroke at 3-6 h after symptom onset

BACKGROUND AND PURPOSE

Intravenous (IV) thrombolysis with recombinant tissue plasminogen activator (rt-PA) has demonstrated favorable clinical outcomes in a 3-6 h window in patients selected with perfusion/diffusion mismatch. However, the advantages of combined IV and intraarterial (IA) thrombolysis after 3 h of stroke onset are unexplored.

METHODS

Acute ischemic stroke patients with persistent occlusion of intracranial large arteries were screened prospectively for thrombolysis by evaluating perfusion/diffusion mismatch on MRI. The IV rt-PA was initiated within 3-6 h, and additional urokinase (UK) was then administered via the IA route after angiography.

RESULTS

Four patients had middle cerebral artery occlusion and one patient had an internal carotid artery occlusion. The median time from the symptom onset to the initiation of IV therapy and to the initiation of IA treatment was 215 +/- 30 min and 292 +/- 41 min, respectively. The median National Institutes of Health Stroke Scale (NIHSS) scores were as follows: initial, 13; immediately after IA treatment, 8; at 24 h, 5; and at 7 days, 3. The Thrombolysis in Myocardial Infarction (TIMI) score after the completion of thrombolysis was 2-3. Four patients without intracerebral hemorrhage recovered completely or exhibited mild disability and one patient with hemorrhage also demonstrated a favorable outcome.

CONCLUSION

This preliminary result suggests that if a significant perfusion/diffusion mismatch on MRI is identified, a sequential combination thrombolysis of IV rt-PA and IA UK is potentially beneficial in moderate to severe acute ischemic stroke patients who are treated within 3-6 h after symptom onset.

Endovascular interventions following intravenous thrombolysis may improve survival and recovery in patients with acute ischemic stroke: a case-control study

BACKGROUND AND PURPOSE

Since the introduction of recombinant tissue plasminogen activator (rtPA) into clinical practice in the mid 1990s, no adjunctive treatment has further improved clinical outcomes in patients with ischemic stroke. The safety, feasibility, and efficacy of combining intravenous (IV) rtPA with endovascular interventions has been described; however, no direct comparative study has yet established whether endovascular interventions after IV rtPA are superior to IV rtPA alone. A retrospective case-control study was designed to address this issue.

MATERIALS AND METHODS

Between 2003 and 2006, 33 consecutive patients with acute ischemic stroke and National Institutes of Health Stroke Scale (NIHSS) scores >/=10 were treated with IV rtPA in combination with endovascular interventions (IV plus intervention) at a tertiary care facility. Outcomes were compared with a control cohort of 30 consecutive patients treated with IV rtPA (IV only) at a comparable facility where endovascular interventions were not available.

RESULTS

Baseline parameters were similar between the 2 groups. We found that the IV-plus-intervention group experienced significantly lower mortality at 90 days (12.1% versus 40.0%, P = .019) with a significantly greater improvement in NIHSS scores by the time of discharge or follow-up (P = .025). In the IV-plus-intervention group, patients with admission NIHSS scores between 10 and 15 and patients </=80 years of age showed the greatest improvement, with a significant change of the NIHSS scores from admission (P = .00015 and P = .013, respectively).

CONCLUSIONS

In this small case-control study of patients with acute ischemic stroke and admission NIHSS scores >/=10, there was a suggestion of incremental clinical benefit among patients receiving endovascular interventions following standard administration of IV rtPA.

Revascularization results in the Interventional Management of Stroke II trial

BACKGROUND AND PURPOSE

Our aim was to detail revascularization results, including impact on outcome and mortality, in the Interventional Management of Stroke (IMS) II trial.

MATERIALS AND METHODS

IMS II was designed to obtain estimates of the efficacy and safety of reduced-dose intravenous recombinant tissue plasminogen activator (rtPA) followed by additional intra-arterial rtPA and low-energy sonography via the EKOS Primo Micro-Infusion Catheter at the occlusion in selected patients with ischemic stroke treated within 3 hours of onset. Revascularization outcomes were detailed and compared with modified Rankin Scale scores 0-2, mortality outcomes, and results from IMS I.

RESULTS

Complete recanalization at 60 minutes occurred in 12 of 29 (41.4%) sonography microcatheter-treated occlusions. Complete recanalization was achieved at 2 hours or procedure end in 20/29 (68.9%) in the ultrasound catheter-treated group, and final thrombolysis in cerebral infarction (TICI) 2/3 reperfusion was achieved in 18/29 (62.0%) ultrasound-treated subjects. Fifteen-minute angiograms demonstrated some recanalization in 69/145 (46.7%) sonography microcatheter treatment intervals, compared with 39/111 (35.1%) in IMS I treatments in 23 subjects with reliable 15-minute angiograms (P = .046). Pooled IMS I-II data demonstrated that partial or complete recanalization occurred in 56/75 (74.6%) and good reperfusion (TICI 2/3) occurred in 46/75 (61.3%) of internal carotid artery T and M1 occlusions. Revascularization correlated with good outcome for TICI 2/3 reperfusion (P = .0004), TICI 2B/3 reperfusion (P = .0002), and arterial occlusive lesion 2/3 recanalization (P = .03).

CONCLUSION

IMS II provides evidence that the EKOS Primo sonography microcatheter exhibits a trend toward improved recanalization of the occlusion compared with a standard microcatheter and again confirms the correlation between recanalization and reperfusion with good clinical outcome and reduced mortality.

Intravenous alteplase for stroke: beyond the guidelines and in particular clinical situations

BACKGROUND AND PURPOSE

Because of the risk of hemorrhage, especially in the brain, thrombolytic therapy with intravenous alteplase is restricted by guidelines, and only a small number of selected patients are being treated. Findings from metaanalyses, post hoc analyses of the randomized trials, and postlicensing experience suggest that more subjects, who otherwise have a poor predicted outcome without treatment, might benefit from intravenous alteplase. Summary of Review- There is a strong indication that treatment may still be beneficial beyond 3 hours up until 4.5 hours. The risk of symptomatic intracerebral hemorrhage is not increased in patients aged 80 years or older. Excluding patients with severe stroke or with early ischemic changes in more than one third of the middle cerebral artery territory on baseline CT scan is probably not necessary when treatment is started <3 hours of symptom onset. Patients with minor or improving symptoms can also benefit. Intravenous thrombolysis appears appropriate as first line therapy for posterior circulation stroke. Alteplase can be given to patients with cervical artery dissection, seizure at onset and evidence of acute ischemia on brain imaging, and after carefully weighing risk and benefit in pregnancy and during menstruation. There are anecdotal reports on its use in children, patients with recent myocardial infarction, cardiac embolus, intracranial aneurysm or arteriovenous malformation, prior stroke and recent surgery. There appears to be a substantially increased risk of symptomatic cerebral hemorrhage in hyperglycemic stroke patients. The combined intravenous and intraarterial approach to recanalization appears safe and is currently under investigation in a randomized trial.

CONCLUSIONS

This document does not intend to change the guidelines but reviews the literature on the use of intravenous alteplase for stroke beyond guidelines and in particular conditions.

A new method for superselective middle cerebral artery infusion in the rat

OBJECT

Selective intraarterial drug delivery is used to achieve enhanced local uptake with reduced systemic side effects. In the present paper the authors describe and characterize a new microcatheter-based model of superselective perfusion of the middle cerebral artery (MCA) in rats combined with blockade of blood flow through the MCA.

METHODS

Selectivity of administration was shown by infusion of Evans blue which diffusely stained the MCA territory, indicating an increased permeability of the blood-brain barrier during the blockade of blood flow to the MCA. Perfusion of autologous blood through the microcatheter resulted in a flow rate-related increase in the cerebral blood flow measured by laser Doppler flowmetry. Similarly, infusion of an artificial O2 carrier, Oxycyte, was accompanied by an increase in tissue oxygenation as measured using a Licox sensor. Blockade of blood flow to the MCA with the new microcatheter for an extended period of time resulted in the development of ischemia, which was comparable to that induced by intravascular occlusion using a silicone-coated thread. In a 24-hour MCA occlusion model, selective administration of a low dose of MK-801 (0.3 mg/kg body weight) resulted in a significantly smaller infarct volume than systemic application (339 +/- 53 mm(3) compared with 508 +/- 26 mm(3), p < 0.001).

CONCLUSIONS

This new model of superselective MCA infusion is a valuable tool for investigating the effect of selective delivery and enhanced drug uptake into cerebral ischemic tissue. Without constant blockade of blood flow through the MCA it may also be useful for enhanced drug uptake, gene transfer, or application of stem cells in other neuropathological conditions.

The Interventional Management of Stroke (IMS) II Study

BACKGROUND AND PURPOSE

The purpose of this study was to further investigate the feasibility and safety of a combined intravenous and intra-arterial approach to recanalization for ischemic stroke.

METHODS

Subjects, ages 18 to 80, with a baseline NIHSS > or =10 had intravenous recombinant tissue plasminogen activator (rt-PA) started (0.6 mg/kg over 30 minutes) within 3 hours of onset. For subjects with an arterial occlusion at angiography, additional rt-PA was administered via the EKOS micro-infusion catheter or a standard microcatheter at the site of the thrombus up to a total dose of 22 mg over 2 hours of infusion or until thrombolysis.

RESULTS

The 81 subjects had a median baseline NIHSS score of 19. The median time to initiation of intravenous rt-PA was 142 minutes as compared with 108 minutes for placebo and 90 minutes for rt-PA-treated subjects in the NINDS rt-PA Stroke Trial (P<0.0001). The 3-month mortality in IMS II subjects was 16% as compared with the mortality of placebo (24%) and rt-PA-treated subjects (21%) in the NINDS rt-PA Stroke Trial. The rate of symptomatic intracerebral hemorrhage in IMS II subjects (9.9%) was not significantly different than that for rt-PA treated subjects in the NINDS t-PA Stroke Trial (6.6%). IMS II subjects had significantly better outcomes at 3 months than NINDS placebo-treated subjects for all end points (OR > or =2.7) and better outcomes than NINDS rt-PA-treated subjects as measured by the Barthel Index and Global Test Statistic.

CONCLUSIONS

A randomized trial of standard intravenous rt-PA as compared with a combined intravenous and intra-arterial approach is warranted and has begun.

Emerging therapies for acute ischemic stroke

Stroke is a major public health problem in the United States and the development of novel therapeutic strategies is an important research priority. Advances in this field are proceeding on several fronts, including the use of next-generation plasminogen activators and glycoprotein IIb/ IIIa inhibitors, refined patient selection with advanced magnetic resonance imaging sequences, endovascular approaches to thrombolysis and thrombectomy, and adjuvant use of ultrasound. There remains no proven therapy for intracerebral hemorrhage, but early results with recombinant activated factor VII look very promising. It is hoped that in the near future, physicians managing patients with acute neurological events will have a robust armamentarium of therapies to bring to bear on both ischemic and hemorrhagic vascular disease.

Intravenous Versus Combined (Intravenous and Intra-Arterial) Thrombolysis in Acute Ischemic Stroke

BACKGROUND AND PURPOSE

Determine feasibility and safety of intravenous (IV) versus combined (IV-IA [intra-arterial]) thrombolysis guided by transcranial color-coded duplex sonography (TCCD).

METHODS

Thirty-three patients eligible for IV thrombolysis, within 3 hours of onset of symptoms, with occlusion in middle cerebral artery territory (TCCD monitoring, thrombolysis in brain ischemia [TIBI] flow grade [0-3]), underwent IV thrombolysis (tissue plasminogen activator, 0.9 mg/kg). In case of recanalization (modification of TIBI score > or =1) after 30 minutes IV thrombolysis was continued over 1 hour; otherwise, it was discontinued, with subsequent IA thrombolysis. Recanalization was determined by TIBI (TCCD) and angiographically by thrombolysis in myocardial infarction (TIMI) flow grades. Clinical outcome measures were assessed at baseline, 24 hours (NIHSS) and 3 months (modified Rankin Scale).

RESULTS

In the IV group, 10/17 patients (59%) with complete or partial recanalization after 30 minutes had a favorable outcome at 3 months (modified Rankin Scale 0 to 2). TIBI flow grades 3 to 5 after 30 minutes of IV thrombolysis predicted a good prognosis compared with TIBI grades 1 to 2 (P<0.05). In the combined IV/IA therapy group (no recanalization after 30 minutes), 9/16 patients (56%) had a favorable outcome at 3 months. One symptomatic intracerebral hemorrhage occurred in each group.

CONCLUSIONS

Combined IV-IA versus IV thrombolysis guided by TCCD was feasible and safe. Recanalization after 30 minutes of IV thrombolysis led to a favorable outcome in 59% of the patients, provided TIBI flow grades were of 3 to 5. In the absence of early recanalization during IV thrombolysis, there was clinical benefit to proceed to IA therapy for a significative proportion of patients (56%).

Hemorrhage in the Interventional Management of Stroke Study

Background and Purpose— The incidence of hemorrhage after combined intravenous (IV) and intra-arterial (IA) recombinant tissue plasminogen activator (rt-PA) was examined in patients entered into the Interventional Management of Stroke (IMS) trial. We also analyzed factors predicting symptomatic and asymptomatic intracerebral hemorrhage (ICH).

Methods— The IMS study treated patients within 3 hours of stroke onset with 0.6 mg/kg IV rt-PA followed by up to 22 mg IA rt-PA. Any hemorrhage within 36 hours associated with clinical deterioration was considered symptomatic. Logistic regression analysis was applied to possibly relevant variables selected from the baseline data to test for associations between these factors and symptomatic hemorrhage, asymptomatic hemorrhage, and all hemorrhage.

Results— Symptomatic hemorrhage occurred in 6% and asymptomatic hemorrhage in 43% of patients. The rate of symptomatic hemorrhage was similar to the National Institute of Neurological Disorders and Stroke (NINDS) trial with IV rt-PA alone. Asymptomatic hemorrhage was more frequent but consistent with the rate observed in more recent IV and IA thrombolytic trials. The small number of symptomatic hemorrhages precluded meaningful analysis of risk factors. Significant factors associated with ICH in univariate analysis were baseline National Institutes of Health Stroke Scale score (asymptomatic and all ICH), edema or mass effect on initial computed tomography (asymptomatic ICH), atrial fibrillation (all ICH), and location of arterial occlusion (internal carotid artery [ICA] compared with middle cerebral artery [MCA]; asymptomatic and all ICH). In multivariate analysis, ICA versus MCA occlusion remained an independent factor associated with asymptomatic and all hemorrhage, and atrial fibrillation was significantly associated with all hemorrhage.

Conclusions— Symptomatic and asymptomatic hemorrhage with combined IV and IA rt-PA occurred at rates similar to previous thrombolytic trials. Site of vascular occlusion and atrial fibrillation may be risk factors for hemorrhagic transformation.

Turning a stroke into a TIA: curative thrombolysis with combined intravenous and intra-arterial tPA

Intravenous tissue plasminogen activator (tPA) is standard treatment for eligible patients with acute ischemic stroke, but may be less effective for very severe strokes caused by proximal intracranial artery occlusions. We report the case of a woman with a devastating stroke who recovered completely following emergency revascularization of an occluded proximal middle cerebral artery using a novel treatment approach that combines both intravenous (IV) and intra-arterial (IA) tPA. This case illustrates the potential value of the combined IV–IA thrombolytic approach, which is an emerging investigational treatment strategy for selected patients with severe acute ischemic stroke.

Future directions for recanalization therapy in acute ischemic stroke

Currently, the only treatment approved by the US Food and Drug Administration for the treatment of acute stroke is the intravenous recombinant tissue plasminogen activator, which must be administered within a 3 h window. The majority of ischemic stroke patients do not receive intravenous thrombolysis, primarily because they enter the healthcare system too late. Alternative treatment strategies being used or investigated include intra-arterial thrombolysis, endovascular clot disruption, and manipulation and angioplasty with or without stenting. The most promising new revascularization technologies beyond conventional thrombolysis for acute ischemic stroke are ultrasound-enhanced thrombolysis, mechanical clot extraction devices and stent angioplasty. Advances in neuroimaging may allow physicians to determine the etiology of a stroke and tailor treatment accordingly for the maximal clinical benefit for affected patients.

Thrombolysis in acute ischemic stroke: successes, failures, and new hopes

Evidence from randomized clinical trials indicates that systemic administration of recombinant tissue plasminogen activator (rtPA) is a highly effective treatment for acute ischemic stroke, provided that treatment is administered within the first 3 h after stroke onset. An absolute increase in favorable outcome of up to 13% has been reported, and a pooled analysis of six randomized trials has shown that, although the sooner rtPA is given the greater the benefit, efficacy is present up to 4.5 h after stroke onset. Despite of the spreading use of tPA in different countries and continents, there are still a number of burdens and failures in the optimal accomplishment of thrombolytic treatment. rtPA is used in less than 4% of patients, reperfusion and complete recovery is achieved in less than 50% of patients, and treatment is denied to many patients. However, important advances in clinical investigation suggest that new aims and hopes will be achieved in the near future. Ultrasound-enhanced systemic thrombolysis, the use of MRI for selecting acute stroke patients for IV or IA thrombolysis after 3 h, mechanical embolus disruption or removal in proximal artery occlusions, and the potential usefulness of new biomarkers of blood brain barrier disruption and hemorrhagic risk are promising strategies that may improve the risk/benefit ratio and increase the number of patients who will benefit from thrombolytic therapy.